Interesting, I'll have to check it out some time.
Another great fast and free image view (although not native x64) is Faststone Image Viewer
. I really like the speed and interface. Been using it as default image viewer for a while now on Windows 7 x64. First heard about it on DPreview.com forums where many pro photographers who use apps like photoshop and lightroom for editing seem to like it for basic image viewing (although it has many editing functions).
What I especially like about it (aside from speed/reliability and support for all raw formats etc.) is that it can be set to auto open images in full screen and its menus and informational displays are hidden (so nothing obscures or interferes with the totally full screen image). But when you want to see info or use menus, they instantly "flyout" when the mouse cursor is moved to the edge of the screen. And also that it can be configured so the scroll wheel will control zooming in & out without having to hold down any other key. Navigation with keys is very intuitive and one can move from viewing an image in FS image viewer directly to one's preferred external editing app.